Surveillance systems and missiles frequently make use of infrared detectors capable of comparing temperature differentials between objects and their backgrounds by comparing their emitted infrared energy, in some cases where the differential is as low as 0.1.degree. K. Missile detectors usually rely largely on the existence of a radiation contrast between the target and the background area, the net radiation from each being caused by both reflection and emission from their surfaces. The detectors are often operable in the wavelength ranges of from 3 to 5 and 8 to 14 micrometers. The wavelength band with which this invention is concerned extends throughout the infrared range and can also be applied to the ultraviolet, visible and millimeter wavebands.
It is known that reflectors have been made to reflect for example the energy from the local environment in the case of an object to be camouflaged so that the detector will fail to "recognise a target", but that system has limitations and is only partially effective, due to difficulty in selecting a region of the local environment to be reflected which has the same radiance as the background to be matched.
It is therefore an object of this invention to provide means which will minimise the differential of the combination of radiation and reflectance between a potential target and its background thereby constituting a "camouflage".